Spin torque transfer technology, also referred to as spin electronics, combines semiconductor technology and magnetics, and is a more recent development. In spin electronics, the spin of an electron, rather than the charge, is used to indicate the presence of digital information. The digital information or data, represented as a “0” or “1”, is storable in the alignment of magnetic moments within a magnetic element. The resistance of the magnetic element depends on the moment's alignment or orientation. The stored state is read from the element by detecting the component's resistive state.
The magnetic element, in general, includes a ferromagnetic pinned layer and a ferromagnetic free layer, each having a magnetization orientation, and a non-magnetic barrier layer therebetween. The magnetization orientations of the free layer and the pinned layer define the resistance of the overall magnetic element. Such an element is generally referred to as a “spin tunneling junction,” “magnetic tunnel junction”, “magnetic tunnel junction cell”, and the like. When the magnetization orientations of the free layer and pinned layer are parallel, the resistance of the element is low. When the magnetization orientations of the free layer and the pinned layer are antiparallel, the resistance of the element is high.
At least because of their small size, it is desirous to use magnetic tunnel junction cell elements in many applications, such as random access memory. However, their small size also creates issues.
One problem in spin torque magnetic random memory (STRAM) is maintaining thermal stability of the magnetic elements at room temperature while at the same time switching each of the multitudes of cells in the acceptable current amplitude range. Due to the distribution of the switching current, the ability to switch every single memory cell using a current with the amplitude in the acceptable range is an issue. It is desired to reduce the switching current needed in order to inhibit thermal instability of the cells.
The present disclosure provides spin torque memory (STRAM) switching schemes that implement magnetic fields to reduce the switching current of the STRAM cell.